Rachael Newham, from mental health group Think Twice, was speaking following calls for Britain to introduce a law to ban models who are excessively thin.
She told Premier: "Many designers will argue that their clothes look better on really skinny people because obviously they hang perhaps in the way they've designed them to, but actually I'd argue that perhaps they should be making clothes for a woman with a really healthy body shape."
She stressed that this cannot be looked at simplistically, however some people will be more susceptible to these images than others: "Those who are vulnerable towards it, perhaps those who feel like they're not good enough or perhaps think they're too fat or too thin - if they're seeing these images, particularly photoshopped images, then they're going to be thinking their body isn't normal."
Earlier this year French MPs joined a number of other countries and approved a law to ban the use of models who have a BMI below a certain level.
The chair of the All Party Parliamentary Group On Body Image, Caroline Nokes, thinks the UK might also need to follow suit in order to ensure a model's Body Mass Index is a certain level.
London Fashion Week begins on Friday.
Listen to Premier's Hannah Tooley speak to Rachael Newham from Think Twice here:
